diff options
Diffstat (limited to 'bootblocks/mbr.s')
| -rw-r--r-- | bootblocks/mbr.s | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/bootblocks/mbr.s b/bootblocks/mbr.s index e633c87..a5e4585 100644 --- a/bootblocks/mbr.s +++ b/bootblocks/mbr.s @@ -10,13 +10,15 @@ ! Space for 12 extra partitions in the 'DiskManager' form that Linux ! _does_ understand. ! -! NB: This needs Dev86 0.15.2 or later +! NB: This needs as86 0.15.2 or later ! Lowest available is $0500, MSDOS appears to use $0600 ... I wonder why? ORGADDR=$0500 preboot=0 ! Include the pre-boot loader. mbrkey=0 ! Option to choose the boot record base on keystroke message=1 ! Display boot message +use512=0 ! Put the end marker at byte 510..512 + diskman=0 ! Disk manager partitions, allows 16 partitions but ! don't overwrite this with a LILO BB. @@ -137,7 +139,7 @@ no_boot: ! SI now has pointer to error message mov si,#crlf call puts tick: - call key_wait + call key_pause j tick else @@ -159,8 +161,7 @@ EOS: keyboot: ! Wait for a key then reboot xor ax,ax int $16 -! int $19 ! This rarely does anything useful... - jmpi $0,$FFFF ! Wam! Try or die! + jmpi $0,$FFFF ! Reboot. press_key: .asciz "\r\nPress return:" @@ -190,9 +191,16 @@ linearise: ! Choose the partition based on a pressed key ... if mbrkey +key_pause: + mov si,#Pause + call puts + j wait_key + key_wait: mov si,#Prompt call puts + +wait_key: mov di,#19 ! Wait for 18-19 ticks next_loop: @@ -214,18 +222,16 @@ bad_key: ret Got_key: + mov ah,#0 ! Clean the kbd buffer. + int $16 + cmp al,#$20 - jnz not_space - mov si,#Pause - j showit -not_space: + jz key_pause ! Recursion !? + mov Showkey,al mov si,#Showkey -showit: call puts - - mov ah,#0 ! Clean the kbd buffer. - int $16 + mov al,Showkey ! ... Now we use our key ... ! 0 => Floppy @@ -270,11 +276,11 @@ EOS: ret Prompt: - .asciz "MBR: " + .asciz "\rMBR 0-4: " Unprompt: - .asciz "\b\b\b\b\b \b\b\b\b\b" + .asciz "\r \r" Pause: - .asciz "\b\b> " + .asciz "\rMBR 0-4> " Showkey: .ascii " " crlf: @@ -393,5 +399,9 @@ diskman_magic: .byte 0xFF endif + if use512 + org ORGADDR+0x1FE + .word 0xAA55 + endif !THE END |